锂离子电池锡基复合氧化物负极材料的研究

采用共沉淀法制备了SnSbO2.5和SnGeO3两种锡基复合氧化物粉末.XRD分析表明,这两种锡基复合氧化物的共同特点是在27°～28°处有波峰,属无定型结构.将其分别作为锂离子电池负极材料的活性物质,利用恒电流电池测试仪研究它们的电化学性能.实验表明,这两种锡基复合氧化物都有较高的电化学容量,SnSbO2.5的可逆容量为1200mA·h/g,SnGeO3的可逆容量为750mA·h/g.这两种锡基复合氧化物的电化学容量远高于碳材料(石墨的理论容量为372mA·h/g),因此,这两种锡基复合氧化物可以作为锂离子电池负极材料的候选材料.     

纳米锡锌复合氧化物贮锂材料的合成和性质

用液相沉淀-热解法合成了一系列结构和组成不同的锂离子电池纳米锡锌复合氧化物贮锂材料, 通过XRD、TEM和电化学测试对材料进行了表征. 测试结果表明, 非晶态ZnSnO3负极材料的初始可逆贮锂容量为844 mA·h/g, ZnO·SnO2负极材料的初始可逆贮锂容量为845 mA·h/g, SnO2·Zn2SnO4复合物负极材料初始可逆贮锂容量为758 mA·h/g, 循环10周后, 三者的充电容量分别为695, 508和455 mA·h/g, 表明非晶态结构的锡锌复合氧化物具有较好的电化学性质, 随着样品中晶体的形成, 该类型负极材料的贮锂性能下降.     

锂离子电池Sn-SBA15负极材料的复合电镀制备及其性能

应用复合电镀法制备Sn-SBA15电极.充放电测试得其初始放电(嵌锂)容量,达到1075mAh/g.充电(脱锂)容量为630mAh/g,经过50周循环后充放电容量均保持在400 mAh/g以上.XRD分析表明,Sn-SBA15电极具有四方晶型锡结构;而SEM观察到电极表面的蜂窝状结构.交流阻抗谱结果显示,Sn-SBA15电极表面有SEI膜的生成.     

锡基非晶态材料的化学合成及其嵌锂性能的初步研究

锂离子电池是近年来化学电源领域研究与发展的热点．为了进一步提高电池的能量密度，开发高容量嵌锂材料是锂离子电池技术发展的关健．目前，广泛应用的嵌锂负极多采用石墨结构碳素材料，其充放电容量已接近ＬｉＣ６的理论比容量３７２ｍＡ·ｈ／ｇ．与此同时，采用其它类...     

锂离子二次电池锡的氧化物负极材料的研究

现有的商品化锂离子二次电池均采用石墨化碳质为负极材料。该类负极材料的制备需要高温（＞２０００℃），而且理论容量有限（＜３７２ｍＡｈ／ｇ），不到金属锂的十分之一。因此人们开展了低温碳材料的研究［１］，可是低温碳材料存在着电压滞后现象，第一次的充放电效率...     

锂离子电池锡氧化物基负极材料的湿化学合成与电化学性质

采用新兴的湿化学方法合成了锡氧化物基粉末材料。用X-射线衍射、扫描电镜和电化学方法对材料的微观结构、形貌和电化学性能进行了详细的研究。结果表明，经400 ℃热处理4 h的锡氧化物基材料的颗粒大小均匀，平均粒径约为200 nm。这种材料的可逆充电容量超过570 mAh·g^-1，30次循环后平均每次循环的容量衰减只有0.15%。良好的电化学性能表明锡氧化物基材料有望作为新一代锂离子电池的负极材料。     

水热法制备无定形ZnSnO3/C复合材料及其电化学性能研究

采用葡萄糖水热碳化法制备了碳包覆无定形ZnSnO3复合材料(ZnSnO3/C),并利用采用X射线衍射、透射电镜、恒电流充放电测试和交流阻抗技术表征、观察与测试样品的结构、形貌以及电化学性能.实验结果表明,ZnSnO3/C复合材料具有典型的核壳结构,ZnSnO3/C复合料表现较高的比容量和优异的循环性能,100周期循环比容量仍保持659 mAh·g-1.     

铈基复合氧化物的结构及其对HCl催化氧化性能的影响

采用氨水共沉淀法制备了一系列铈基复合氧化物(Ce0.9M0.1O2,M=Cu、Cr、Zr、Ti、La),借助XRD、Raman、N2吸附-脱附、ESEM和H2-TPR等手段对复合氧化物的结构进行了表征,并考察了其在HCl催化氧化制Cl2过程中的性能.结果显示:Cu、Cr和Zr掺杂能显著减小复合氧化物晶粒尺寸,提高复合氧化物的比表面积和孔容,并提供更多的低温可还原氧物种.而La和Ti的掺杂可以获得较大的表面氧空位浓度以及增加高温可还原氧物种数目.复合氧化物结构和表面性质的变化显著影响了其HCl催化氧化活性,在430℃下铈基复合氧化物催化剂活性顺序为:Ce0.9Cu0.1O2Ce0.9Cr0.1O2Ce0.9Zr0.1O2Ce0.9Ti0.1O2Ce O2Ce0.9La0.1O2,低温可还原氧物种数目直接与催化剂活性有关.反应动力学测试显示催化剂低温可还原氧物种有利于HCl在催化剂表面的吸附和活化,而催化剂表面的氧空位可以促进氧分子的吸附和活化.     

硬模板法制备铈基复合氧化物及其对甲苯燃烧的催化性能

采用硬模板法制得CeM-HT(M=Cu、Mn、Fe和Co)复合氧化物催化剂,借助XRD、BET、O₂-TPD和H₂-TPR研究了催化剂的物理化学性质,通过甲苯催化燃烧探针反应评价了催化剂的催化性能。结果表明,CuO、MnO_x、FeO_x和Co₃O₄能溶入CeO₂晶格形成Ce-O-Cu、Ce-O-Mn、Ce-O-Fe和Ce-O-Co固溶体,Cu和Mn离子的溶入导致CeO₂晶格发生了较大程度的晶格畸变,Fe和Co离子对CeO₂晶格的影响较小,且在CeCo-HT氧化物催化剂中还存在微量晶相Co₃O₄。所制得的CeM-HT氧化物催化剂表现出了优越的甲苯催化燃烧性能,在反应温度为300、270、260和230 ℃时,CeFe-HT、CeCo-HT、CeMn-HT和CeCu-HT氧化物催化剂上甲苯的催化燃烧转化率分别达93.7%、95.0%、96.5%和95.0%以上。Ce基复合氧化物催化剂的甲苯催化燃烧活性顺序与其氧脱附性能、储氧性能和可还原性能具有正相关性,遵从顺序为CeCu-HT > CeMn-HT > CeCo-HT > CeFe-HT。     

锂离子电池锡薄膜负极制备及电化学性能研究

应用真空蒸发法在泡沫铜基底上制备锡薄膜负极.XRD、SEM分析表征薄膜的物相结构及其微观形貌,并测试了材料的电化学性能.结果表明,泡沫铜基底的三维结构增强了活性物质与基底的结合力.在同一基底温度下,锡颗粒随蒸发时间延长逐渐增大,电池电化学性能降低;而在同一时间内,升高基底温度,颗粒无明显变化,电池循环寿命有了很大提高.样品A″电池(基底温度:200℃,蒸发时间:0.5 h)经100次充放电循环后比容量仍达407.3 mAh·g-1.     

Excellent Electrochemical Properties of Yolk–Shell MoO3 Microspheres Formed by Combustion of Molybdenum Oxide–Carbon Composite Microspheres

Yolk–shell MoO₃ microspheres are prepared by a two‐step process in which molybdenum oxide–carbon (MoO_x–C) composite microspheres are first obtained by spray pyrolysis, followed by combustion at 400 °C in air. The yolk–shell microspheres exhibit excellent electrochemical properties and structural stability.     

锂离子电池锡基合金体系负极研究

综述了锂离子电池锡基金属间化合物和复合物负极的研究进展。介绍了锡基合金体系作锂离子电池负极的优势, 指出了锡金属负极的不足,提出了采用锡基合金及其复合物是克服锡金属负极主体材料尺寸稳定问题的解决办法。概述了各种锡基合金和其复合物的结构、电化学性能、相应的加工方法和某些反应机理,总结了这些材料的优点和缺点,提出了改进这些材料性能的一些建议,如采用分散形态的纳米颗粒结构或用非晶合金并控制形态结构的转变,着重指出多相锡基锂合金复合物是最有前景的负极材料。     

A New Concept for Obtaining SnO2 Fiber‐in‐Tube Nanostructures with Superior Electrochemical Properties

Tin oxide (SnO₂) nanotubes with a fiber‐in‐tube structure have been prepared by electrospinning and the mechanism of their formation has been investigated. Tin oxide‐carbon composite nanofibers with a filled structure were formed as an intermediate product, which were then transformed into SnO₂ nanotubes with a fiber‐in‐tube structure during heat treatment at 500 °C. Nanofibers with a diameter of 85 nm were found to be located inside hollow nanotubes with an outer diameter of 260 nm. The prepared SnO₂ nanotubes had well‐developed mesopores. The discharge capacities of the SnO₂ nanotubes at the 2nd and 300th cycles at a current density of 1 A g^?1 were measured as 720 and 640 mA h g^?1, respectively, and the corresponding capacity retention measured from the 2nd cycle was 88 %. The discharge capacities of the SnO₂ nanotubes at incrementally increased current densities of 0.5, 1.5, 3, and 5 A g^?1 were 774, 711, 652, and 591 mA h g^?1, respectively. The SnO₂ nanotubes with a fiber‐in‐tube structure showed superior cycling and rate performances compared to those of SnO₂ nanopowder. The unique structure of the SnO₂ nanotubes with a fiber@void@tube configuration improves their electrochemical properties by reducing the diffusion length of the lithium ions, and also imparts greater stability during electrochemical cycling.     

General Synthesis of Multi‐Shelled Mixed Metal Oxide Hollow Spheres with Superior Lithium Storage Properties

Complex hollow structures of transition metal oxides, especially mixed metal oxides, could be promising for different applications such as lithium ion batteries. However, it remains a great challenge to fabricate well‐defined hollow spheres with multiple shells for mixed transition metal oxides. Herein, we have developed a new “penetration–solidification–annealing” strategy which can realize the synthesis of various mixed metal oxide multi‐shelled hollow spheres. Importantly, it is found that multi‐shelled hollow spheres possess impressive lithium storage properties with both high specific capacity and excellent cycling stability. Specifically, the carbon‐coated CoMn₂O₄ triple‐shelled hollow spheres exhibit a specific capacity of 726.7 mA h g^?1 and a nearly 100 % capacity retention after 200 cycles. The present general strategy could represent a milestone in design and synthesis of mixed metal oxide complex hollow spheres and their promising uses in different areas.     

Lithium‐Rich Layered Oxide Li1.18Ni0.15Co0.15Mn0.52O2 as the Cathode Material for Hybrid Sodium‐Ion Batteries

Li‐rich layered oxide Li_1.18Ni_0.15Co_0.15Mn_0.52O₂ (LNCM) is, for the first time, examined as the positive electrode for hybrid sodium‐ion battery and its Na⁺ storage properties are comprehensively studied in terms of galvanostatic charge–discharge curves, cyclic voltammetry and rate capability. LNCM in the proposed sodium‐ion battery demonstrates good rate capability whose discharge capacity reaches about 90 mA h g^?1 at 10 C rate and excellent cycle stability with specific capacity of about 105 mA h g^?1 for 200 cycles at 5 C rate. Moreover, ex situ ICP‐OES suggests interesting mixed‐ions migration processes: In the initial two cycles, only Li⁺ can intercalate into the LNCM cathode, whereas both Li⁺ and Na⁺ work together as the electrochemical cycles increase. Also the structural evolution of LNCM is examined in terms of ex situ XRD pattern at the end of various charge–discharge scans. The strong insight obtained from this study could be beneficial to the design of new layered cathode materials for future rechargeable sodium‐ion batteries.     

Preparation of Li4Ti5O12 Yolk–Shell Powders by Spray Pyrolysis and their Electrochemical Properties

We have reported for the first time the preparation of yolk–shell‐structured Li₄Ti₅O₁₂ powders for use as anode materials in lithium‐ion batteries. One Li₄Ti₅O₁₂ yolk–shell‐particle powder is directly formed from each droplet containing lithium, titanium, and carbon components inside the hot wall reactor maintained at 900 °C. The precursor Li₄Ti₅O₁₂ yolk–shell‐particle powders, which are directly prepared by spray pyrolysis, have initial discharge and charge capacities of 155 and 122 mA h g^?1, respectively, at a current density of 175 mA g^?1. Post‐treatment of the yolk–shell‐particle powders at temperatures of 700 and 800 °C improves the initial discharge and charge capacities. The initial discharge capacities of the Li₄Ti₅O₁₂ powders with a yolk–shell structure and a dense structure post‐treated at 800 °C are 189 and 168 mA h g^?1, respectively. After 100 cycles, the corresponding capacities are 172 and 152 mA h g^?1, respectively (retentions of 91 and 90 %).     

锂离子电池锂锰氧化物高压嵌锂材料的结构和电化学性能研究

利 用 Ｘ Ｒ Ｄ、 Ｉ Ｃ Ｐ、 Ｔ Ｇ Ａ 、 Ｄ Ｔ Ａ 及 恒 流 充 放 电 等 方 法 研 究 分 析 了 一 种 特 殊 天 然 结 构 Ｍｎ Ｏ２（ Ｎ Ｍ Ｄ） 材料的结 构、组成 以及电 化学嵌锂 特性． Ｘ Ｒ Ｄ 分析 表明,该样 品材料 是由钠水 锰矿以及水羟 锰矿复 合结构组 成的 Ｍｎ Ｏ２ 纳米 纤 维． 充放 电 循环 结果 显 示,其 前 期循 环容 量 可高 达 １５０ｍ Ａｈ／ ｇ 左 右,但性 能尚不够 稳定． 本文采 用一种 水热法高 压嵌锂处 理,可将 Ｎ Ｍ Ｄ 样品 转变为 具有３ ×３ 大隧道结 构的钡 镁锰矿（ Ｔｏｄｏｒｏｋｉｔｅ） 型锂 锰氧 化 物,既 增 强了 Ｌｉ ＋ 嵌 入 隧道 或 层间 结 构 的循环稳定 性． 并 显著提 高锂锰氧 化物电 极材料性 能的 稳定 性,以 充放 电电 流密 度 为０ ．８ ｍ Ａ／ｃ ｍ ２ ,经过１８０ 次 循环后 其比容量 仍具有 １１０ ｍ Ａｈ／ ｇ ． 该类 大隧道结 构锂锰 氧化物可 作为一 种３ Ｖ 的锂离子电极 材料．     

Facile Mechanochemical Synthesis of Nano SnO2/Graphene Composite from Coarse Metallic Sn and Graphite Oxide: An Outstanding Anode Material for Lithium‐Ion Batteries

A facile method for the large‐scale synthesis of SnO₂ nanocrystal/graphene composites by using coarse metallic Sn particles and cheap graphite oxide (GO) as raw materials is demonstrated. This method uses simple ball milling to realize a mechanochemical reaction between Sn particles and GO. After the reaction, the initial coarse Sn particles with sizes of 3–30 μm are converted to SnO₂ nanocrystals (approximately 4 nm) while GO is reduced to graphene. Composite with different grinding times (1 h 20 min, 2 h 20 min or 8 h 20 min, abbreviated to 1, 2 or 8 h below) and raw material ratios (Sn:GO, 1:2, 1:1, 2:1, w/w) are investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, field‐emission scanning electron microscopy and transmission electron microscopy. The as‐prepared SnO₂/graphene composite with a grinding time of 8 h and raw material ratio of 1:1 forms micrometer‐sized architected chips composed of composite sheets, and demonstrates a high tap density of 1.53 g cm^?3. By using such composites as anode material for LIBs, a high specific capacity of 891 mA h g^?1 is achieved even after 50 cycles at 100 mA g^?1.